Messing with the Door is a good, if potentially dangerous, idea! Of course, experimenting will need to be done carefully and over a good amount of time, given the difficulty of working directly with the Door. Sorrow would be interested in both of their ideas, with a mild preference for the first because it's much harder to 'test-run' sending an entire species into another universe.

They could experiment with both ideas, and possibly others that they come up with. It would involve a lot of exposure to the Door, and attempting to increase the madness effects would possibly affect the rest of the city (or at least parts of it). It'll definitely be psychologically difficult on everyone working with the Door.

Let us know what the group chooses to focus on, and we can give you further effects and things to work with!